The Evidence Base for Coaching Effectiveness
A structured reference document for leaders and organizations who want to evaluate coaching as a business investment — not an act of faith.
If you are evaluating coaching, you are probably asking the wrong question first.
Most organizations start with: which coach should we hire?
The more useful question is: how will we know if it worked?
Before selecting a coach, structuring an engagement, or approving a budget, senior leaders deserve a clear answer to what the research actually shows — what coaching changes, how reliably, under what conditions, and how outcomes can be measured without relying on participant satisfaction alone.
This reference document provides that answer.
What the Research Shows — and What It Does Not
There is now a substantial body of peer-reviewed evidence on coaching effectiveness.
It is consistent enough to take seriously.
It is also imperfect enough to require careful reading.
The evidence confirms that coaching produces measurable, statistically significant effects on:
- Goal attainment and behavioral change
- Decision-making quality and leadership performance
- Individual well-being, coping capacity, and work attitudes
- Team engagement, escalation reduction, and execution speed
It does not confirm that coaching always works, that ROI figures cited in the market are universally applicable, or that more sessions produce proportionally better outcomes.
The research is more nuanced than most practitioners acknowledge, and more robust than most skeptics assume.
What You Will Receive
The Evidence Base for Executive Coaching is a structured reference document covering the full breadth of coaching effectiveness research.
Inside, you will find:
- Annotated summaries of six peer-reviewed meta-analyses, including two RCT-only studies representing the highest available methodological standard
- A consolidated effect size reference table across all major outcome domains
- An overview of major industry studies — with explicit notes on where their methodology is strong and where it requires qualification
- Evidence from adjacent domains: medicine, surgery, and sales performance, where coaching outcomes are objectively measurable
- A documented overview of the conditions under which coaching reliably does not work
- A full bibliography of 23 primary sources, traceable to original academic and practitioner publications
This is not a sales document for coaching.
It is a working reference for leaders and organizations who want to make evidence-informed decisions about coaching investments — including when not to make them.
Who This Is For
This document is designed for:
- CEOs, COOs and Executive Team members evaluating coaching as a leadership development instrument
- HR Directors and L&D leaders building the business case for a coaching program
- Operations and Transformation Leaders seeking to connect behavioral change to measurable performance outcomes
- Senior Managers and Governance Bodies responsible for approving and evaluating people development investments
It is not a primer on what coaching is or how to find a coach.
It is a structured evidence base for leaders who already understand the value proposition and want to know what the research actually supports — and what it does not.
If you want to evaluate coaching with the same rigour you would apply to any other significant business investment, this document provides the foundation.
About the Author
Jan Salomons is a leadership advisor and executive coach with more than 35 years of management experience and over 20 years working with senior leadership teams.
His work focuses on leadership system design, governance discipline and execution in complex operational and regulated environments.
He is a member of the Harvard Business Review Advisory Council and supports executive teams in strengthening decision clarity, accountability and structural performance.
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